This invention relates generally to bird feeders, and in particular to such a feeder in which the bottom of its feed-containing trough has a water pervious screen that may be removed for cleaning in sub-freezing temperatures.
For a number of years, the troughs of bird feeders have been provided with screens to enable drainage of rainwater or melted snow therethrough, to keep the feed dry. Prior to that, feed and shucks of seed such as sunflower would accumulate and cake, and, especially if the temperature were below freezing, would freeze into hard-to-remove clumps. Cleaning was difficult, but had to be done in order for fresh seed to move downwardly by gravity from the conventional hopper into the trough. In addition, bird excrement would sometimes accumulate with the seed residue and would place birds at risk from spread of disease. Their excrement sometimes also acted as a binding agent, effectively gluing the expended seed remains to the bottom. This made cleaning somewhat difficult, even in temperatures above freezing.
Once the bird feeder industry went in fairly large measure with drainable bottom screens, liquid would pass through a perforated bottom, but the residue would still continue to pile up. Frozen clumping was not nearly as much of a problem because of water passing through the screen, but remained still. This required feeders to be removed and inverted for cleaning, until designs appeared in which the bottom screens were made to be horizontally slidable, much like the slide of a drawer. This was a valuable improvement in the art since the feeder did not then have to be removed from its post or chain. However, the manner in which the sliding bottom screen was supported, typically in grooves in the wooden sides of the trough, created a new problem when feeding birds in cold climates during winter. That is the period when bird feeding is most essential to preserve wildlife, since birds have difficulty getting food without the help of humans during winter. And if the wood from which the feeder is typically made expands from moisture at the same time seed residues tend to cake in the screen grooves and on the bottom of the trough, removing the slidable screen becomes difficult in some instances, near impossible in others. Obviously, the longer the period between cleanings of the trough because of freezing conditions, the more susceptible the birds will become to disease being spread from one bird to another and from one species to another. The need remained for enabling a screen to be removed easily and rapidly for cleaning a feeder in freezing temperatures.
A bird feeder is provided with a metallic perforate trough bottom that is supported on its underside on ledges consisting of a plastic material on which water tends to bead rather than sheet, and which plastic material is essentially self-lubricating and thereby non-caking and non-sticking. Preferably, the material is also ultra-violet ray resistant and is therefore capable of long life in the outdoors, maintaining its other desired characteristics for a considerable period. The end goal is to provide easy and quick feeder cleaning capabilities, especially in sub-freezing temperatures.
A principal object of the invention is to provide a bottom screen for a bird feeder trough, which screen is supported in a manner making it capable of easy and quick removal and reinstallation, particularly in freezing temperatures.
A further object is to provide a removable metal screen at the bottom of a bird feeder trough, and to support that screen solely on plastic ledges having a slick surface on which water only tends to bead.
An ancillary object is to support such a metal screen in a manner that it does not come into contact with moisture absorbent wooden portions of the structure.
More specifically, an object is to provide ledges for the screen, which ledges are made from a plastic material that is impervious to water, and which ledges have self-lubricating and non-caking characteristics.
Still more specifically, an object is to provide ledges that are made of an ultra-high molecular weight polyethylene that is preferably resistant to the rays of ultra-violet light.
Other objects will become apparent from the following description, in which reference is made to the accompanying drawings.